SLOA198A September   2014  – December 2021 DRV2665 , DRV2667 , DRV2700 , DRV8662

 

  1.   Trademarks
  2. 1 Boost Converter Basics
  3. 2 DRV8662, DRV2700, DRV2665, and DRV2667 Boost Converter
    1. 2.1 DRV8662, DRV2700, DRV2665, and DRV2667 Boost Converter Efficiency
      1. 2.1.1 Boost Efficiency vs Boost Current
    2. 2.2 DRV8662, DRV2700, DRV2665, and DRV2667 Boost Converter Load Regulation
      1. 2.2.1 Boost Regulation vs Current
  4. 3 Configuring the Boost Converter
  5. 4 Boost Converter Output Voltage
  6. 5 Calculating the Load Current
  7. 6 Selecting an Inductor
    1. 6.1 Inductance Rating
    2. 6.2 Saturation Current Rating
    3. 6.3 Thermal Current Rating
    4. 6.4 Choosing REXT
    5. 6.5 What to Avoid: Using Incorrect Inductor Current Ratings
  8. 7 Calculate the Maximum Boost Current
  9. 8 Output Capacitor Selection
  10. 9 Input Capacitor Selection
  11. 10PCB Layout
    1. 10.1 What to Avoid: Incorrect Inductor Placement
  12. 11Examples
    1. 11.1 Example: Based on the DRV8662EVM
      1. 11.1.1 Configure the Boost Voltage
      2. 11.1.2 Configure the Inductor Current
      3. 11.1.3 Boost Performance Results
    2. 11.2 Example: Based on the DRV2667EVM-CT with 25-nF Piezo Module
      1. 11.2.1 Configure the Boost Voltage
      2. 11.2.2 Configure the Inductor Current
      3. 11.2.3 Boost Performance Results
  13. 12Revision History

1 Boost Converter Basics

A boost converter, as the name implies, converts a low voltage power rail and boosts it to a higher voltage. A boost converter consists of three main components: an inductor, a switch (MOSFET), and a diode. The basic boost converter schematic is shown in the following figure.

GUID-2B5C40A2-CE41-4FFF-9143-16FAEE4A522F-low.gif

To convert the low voltage to a high voltage, the boost converter operates in two phases. In the first phase the inductor is charged by closing the switch and forcing current through the inductor to ground. During this period the current through the inductor increases allowing the inductor to store charge.

GUID-E28DE3E3-FF89-45FA-B014-2AB4F0EA899F-low.gif

Once the inductor current reaches a maximum threshold, the switch opens and forces the inductor to dump the stored charge through the diode and onto the output capacitor and load.

GUID-61257F54-4E41-4EB6-83A6-B02F1E4FC163-low.gif

By repeating this charge and dump process, the boost converter is able to increase the output voltage.